eCall refers to an in-vehicle emergency call service. In the event of a collision involving the vehicle, the eCall In-Vehicle System (IVS) establishes an emergency call via a mobile network to emergency agencies. The IVS can be provisioned for “eCall-only” service or for “mixed-mode eCall” service. In mixed-mode eCall service, the system can be used to perform emergency eCalls as well as non-emergency, subscription-based calls. In eCall-only mode, however, the system can only be activated to make emergency calls, and an IVS in eCall-only mode does not register on the mobile network before the eCall is triggered. Thus, when an eCall emergency is triggered, two operations must be performed: (1) the IVS must first register on an available mobile network, and then (2) the IVS initiates the eCall emergency call. Conventionally, registration of the IVS on the mobile network to place an eCall is performed similar to registration for non-emergency calls.
When the IVS is “roaming” and its Home Public Land Mobile Network (HPLMN) or “home network” is unavailable, the IVS must register on a Visitor Public Land Mobile Network (VPLMNs) or “roaming network” if one is available. It may be the case that no network is available or that an available network can only provide limited service, in which case eCall may be inoperable—for example, where the IVS itself cannot initiate eCall from limited service areas, or the roaming network cannot accept an emergency call in a limited service area (as may be the case in certain European countries). Moreover, even when a roaming network is available, it must receive permission from the IVS's home network before the roaming network can register the IVS. It is not uncommon for such permission to be denied, especially in typical instances where the home network has a roaming registration management policy (RRMP) that only permits registrations (and subsequent call servicing) by preferred VPLMN partners (“preferred partners”) with whom the home network has established favorable business arrangements. Thus, in operation, the home network might automatically reject registrations from non-preferred roaming networks unless and until it receives and accepts a registration request through one of its preferred partners.
Whereas a typical mobile phone user might become aware of these issues (no service, limited-but-unusable service, etc.) when the mobile phone is powered on or roams into a visited network (e.g., the mobile phone may provide a “no service” message or signal to the user) or the first time a user attempts to place a call and thus may be able to take steps to correct the situation, an eCall-only subscriber will be entirely unaware of these issues because the eCall-only IVS attempts to connect to a network only after an emergency has arisen and time is of the essence. In other words, to make an emergency call while roaming, an eCall-only IVS not only has to find service (and risk that no service is available) but may also have to attempt registering with several available roaming networks before one is finally accepted by the IVS's home network (if at all), and this may take several minutes to succeed (if ever). Thus, network availability and conventional roaming registration of the IVS on the mobile network may significantly delay the placing of the emergency call—a call that is critically important to successfully register as quickly as possible.